Adrian Murphy

Bio: Adrian Murphy is an academic researcher from Queen's University Belfast. The author has contributed to research in topics: Buckling & Lightning strike. The author has an hindex of 18, co-authored 172 publications receiving 1302 citations. Previous affiliations of Adrian Murphy include General Dynamics & Dublin City University.

Technical challenges and opportunities in realising a circular economy for waste photovoltaic modules

Abstract: The global exponential increase in annual photovoltaic (PV) installations and the resultant levels of PV waste is an increasing concern. It is estimated by 2050 there will be between 60 and 78 million tonnes of PV waste in circulation. This review will investigate and establish the most efficient routes to recycle end-of-life modules. It will consider current design constraints, focusing on the maximum recovery of constituents from the module, reporting on some of the latest advancements in recycling methodology at both industrial and laboratory scale. Circular challenges, opportunities, models and arguments are presented for critical analysis of closed-loop recycling alongside alternative open-loop cascading options. Adopting circular economy principles will help offset environmental factors such as emissions associated with the manufacturing stages and increase recycling & recovery rates. First-generation crystalline silicon (c-Si) modules have had an 80–90% market share over the last 40 years and will constitute the majority of the impending PV waste stream. These PV modules are composed of several material types such as glass, metal, semiconductor and polymer layers in a strongly bound laminate. This design makes reusing and maintaining these modules difficult and limits potential recycling options. Here we provide guidance for understanding the c-Si PV module manufacturing process and how to best approach the challenge of recycling this vast and inevitable waste stream. In conclusion, pyrolysis offers the best potential for the optimum recovery of material and energy found in first-generation c-Si modules to help promote a truly circular economy within the well-established PV industry.

The Computational Post Buckling Analysis Of Fuselage Stiffened Panels Loaded In Compression

Abstract: Fuselage panels are commonly fabricated as skin–stringer constructions, which are permitted to locally buckle under normal flight loads. The current analysis methodologies used to determine the post buckling response behaviour of stiffened panels relies on applying simplifying assumptions with semi-empirical/empirical data. Using the finite element method and employing non-linear material and geometric analysis procedures, it is possible to model the post buckling behaviour of stiffened panels without having to place the same emphases on simplifying assumptions or empirical data. Investigation of element, mesh, idealisation, imperfection and solution procedure selection has been undertaken, with results validated against mechanical tests. The research undertaken has demonstrated that using a commercial implicit code, the finite element method can be used successfully to model the post buckling behaviour of flat riveted panels. The work has generated a series of guidelines for the non-linear computational analysis of flat riveted panels subjected to uniform axial compression.

Stiffened panel stability behaviour and performance gains with plate prismatic sub-stiffening

Abstract: To increase the structural efficiency of integrally machined aluminium alloy stiffened panels, it is plausible to introduce plate sub-stiffening to increase the local stability and thus panel static strength performance. Reported herein is the experimental validation of prismatic sub-stiffening, and the computational verification of such concepts within larger recurring structure. The experimental work demonstrates the potential to ‘control’ plate buckling modes. For the tested sub-stiffening design, an initial plate buckling performance gain of +89% over an equivalent mass design was measured. The numerical simulations, modelling the tested sub-stiffening design, demonstrate equivalent behaviour and performance gains (+66%) within larger structures consisting of recurring panels.

Assessment of the energy recovery potential of waste Photovoltaic (PV) modules

Abstract: Global exponential increase in levels of Photovoltaic (PV) module waste is an increasing concern. The purpose of this study is to investigate if there is energy value in the polymers contained within first-generation crystalline silicon (c-Si) PV modules to help contribute positively to recycling rates and the circular economy. One such thermochemical conversion method that appeals to this application is pyrolysis. As c-Si PV modules are made up of glass, metal, semiconductor and polymer layers; pyrolysis has potential not to promote chemical oxidation of any of these layers to help aid delamination and subsequently, recovery. Herein, we analysed both used polymers taken from a deconstructed used PV module and virgin-grade polymers prior to manufacture to determine if any properties or thermal behaviours had changed. The calorific values of the used and virgin-grade Ethylene vinyl acetate (EVA) encapsulant were found to be high, unchanged and comparable to that of biodiesel at 39.51 and 39.87 MJ.Kg−1, respectively. This result signifies that there is energy value within used modules. As such, this study has assessed the pyrolysis behaviour of PV cells and has indicated the energy recovery potential within the used polymers found in c-Si PV modules.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

American Society for Testing and Materials

Abstract: The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.